pub fn search<'a>(query:&str, contents:&'a str)->Vec<&'a str> {
    let mut results = Vec::new();
    for line in contents.lines() {
        if line.contains(query){
            results.push(line);
        }
    }
    results
}

#[cfg(test)]
mod tests{
    use super::*;
    #[test]
    fn one_result() {
        let query = "duct";
        let contents = "\
Rust:
safe, fast, productive.
Pick three.";

        assert_eq!(
            vec!["safe, fast, productive."],
            search(query, contents)
        );
    }
}